package com.lxp.filter;

import com.alibaba.fastjson.JSON;
import com.lxp.common.R;
import com.lxp.utlis.BaseContext;
import org.springframework.util.AntPathMatcher;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * @author lxp
 * @Motto 每天一行小代码，健康幸福学JAVA：
 * @create 2022-08-23 15:45
 * @Description:  检查当前用户是否完成登录的过滤器
 */

@WebFilter(filterName = "loginCheckFilter",urlPatterns = "/*")
public class LoginCheckFilter implements Filter {

    // 路径匹配器，支持通配符
    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        //  1、获取本次请求的URI
        String requestURI = request.getRequestURI();
        //  1.1、定义不需要处理的请求路径
        String[] urls = new String[]{
                "/employee/login",
                "/employee/logout",
                "/static/backend/**",
                "/static/front/**"
        };

        //  2、判断本次请求是否需要处理
        boolean check = check(urls, requestURI);

        // 3、如果不需要处理，则直接放行
        if (check){
            filterChain.doFilter(request,response);
            return;
        }

        // 4、判断登录状态，如果已登录，则直接放行
        if (request.getSession().getAttribute("employee") != null){

            // 在当前线程设置 登录人的ID
            Long empId = (Long) request.getSession().getAttribute("employee");
            BaseContext.setCurrentId(empId);

            filterChain.doFilter(request,response);
            return;
        }
        // 5、如果未登录则返回未登录结果,通过输出流的方式向客户端页面响应
        response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));
        return;
    }

    /**
     * 路径匹配，检查本次请求是否需要放行
     * @param urls
     * @param requestURI
     * @return
     */
    public boolean check(String[] urls,String requestURI){
        for (String url : urls) {
            boolean match = PATH_MATCHER.match(url, requestURI);
            if (match){
                return true;
            }
        }
        return false;
    }

}
